For many years the Hebrew people were tied to the hip with God, but in Exodus 32, Moses had gone up on Mt Sinai to get direction from God, and the people were impatient because Moses was taking too long, which meant God was taking too long. So they decided that they no longer wanted this invisible God to lead them, they wanted something tangible, so they gathered all their jewelry together and melted it and they built a Golden Calf.